Improve Android gdbserver and gdb_ex scripts

platform_tools/android/bin/android_gdbserver

 #!/bin/bash
 #
 # android_gdbserver: Pushes gdbserver. Starts debugging environment.
 
 SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 source $SCRIPT_DIR/android_setup.sh
 source $SCRIPT_DIR/utils/setup_adb.sh
 
 APP_NAME=${APP_ARGS[0]}
 PORT=5039
 
 BUILD_DIR="${SKIA_OUT}/${BUILDTYPE}"
 TARGET_LIBRARY="${BUILD_DIR}/lib/lib${APP_NAME}.so"
 if [ ! -f "$TARGET_LIBRARY" ]
 then
   echo "Unable to find the ${APP_NAME} library at ${TARGET_LIBRARY}."
   exit 1
 fi
 
 # We need the debug symbols from these files
 GDB_TMP_DIR=$(pwd)/android_gdb_tmp
-mkdir $GDB_TMP_DIR
+mkdir -p $GDB_TMP_DIR
 
 echo "Copying symbol files"
 SYSTEM_LIBRARY_PATH=/system/lib
 for library_file in \
     libc.so \
     libstdc++.so \
     libm.so \
     liblog.so \
     libz.so \
     libcutils.so \
@@ skipping 27 matching lines @@
 $ADB forward "tcp:5039" "tcp:5039"
 
 # Kill all previous instances of gdbserver and the app to rid all port overriding errors.
 echo "Killing any running Skia processes."
 $ADB shell ps | grep gdbserver | awk '{print $2}' | xargs $ADB shell kill
 $ADB shell ps | grep ${APP_NAME} | awk '{print $2}' | xargs $ADB shell kill
 
 # Starting up gdbserver in android shell
 echo "Starting gdbserver with command: ${APP_ARGS[@]}"
 $ADB shell /data/local/tmp/gdbserver :5039 /data/local/tmp/skia_launcher ${APP_ARGS[@]} &